Sierra has released two new Tipped MatchKing (TMK®) bullets that should find favor with PRS competitors and tactical shooters*. Sierra is producing a new 95 grain 6mm projectile and a new 130 grain 6.5mm bullet. Both feature acetal resin tips that lower drag by improving the ballistic coefficient (BC) and making the BC more uniform from bullet to bullet. The 95-grainer should work well as a higher-speed option in the .243 Win, 6mm Creedmoor, 6mm Dasher, and 6mmBR. We were able to push other 95gr bullets nearly 100 fps faster than 105gr bullets from a 6mmBR. For those shooting the 6.5×47 Lapua and 6.5 Creedmoor, the new 130gr TMK should be a near-ideal bullet weight. We know that Berger’s 6.5mm 130gr VLD works great in those mid-sized cartridges, so Sierra’s new 130-grainer should be in the “sweet spot”. Also, in the .260 Remington the 130gr TMK should be capable of velocities that hit predicted accuracy nodes with ease. The 6mm 95 grain TMK requires a twist rate of 1:9″ or faster to stabilize while the 6.5mm 130 grain TMK requires a twist rate of 1:8″ or faster to stabilize.
We expect the 130gr 6.5mm TMK to find favor with Tactical Shooters
* In addition, Sierra plans to add a 7mm 160gr TMK to the line-up, product #7660, but we don’t expect this to be used for tactical games because of the heavier recoil.
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Here’s something you don’t see very often — Lapua cartridge brass on sale. As part of its Back-to-Black promotion, Brownells has deeply discounted its inventories of Lapua Brass. For most cartridges/calibers, the price has been reduced at least $10.00 per 100-count box. Here are the sale prices, good through the end of the week:
What kind of 200-yard accuracy can you get in an enclosed, underground test range? Would you believe 0.162 MOA at 200 yards with a .338? Have a look at these test targets from Sierra Bullets. Like most bullet manufacturers, Sierra does live-fire bullet testing to ensure that Sierra projectiles perform as promised, with repeatable accuracy. Sierra tests bullets in its own underground test complex. Sierra’s 300-meter test range is the longest, privately-owned underground bullet test facility in the world. Sierra offers free tours of the test tunnel as part of Sierra’s Factory Tour Program.
Day in and day out, various bullet types are tested using a big collection of barreled actions. These barreled actions are clamped in stout, return-to-battery test fixtures. These big, heavy test fixtures provide near-perfect repeatability (with no human-induced holding or aiming errors).
Sierra Bullets 10-Shot Groups at 200 yards
Check out these 10-shot test groups shot at the Sierra Test Range at 200 yards. Note that the numbers listed on each sample are actual measurements in inches. To convert to MOA, cut those numbers in half (to be more precise, divide by 2.094, which is 1 MOA at 200 yards). For example, the 0.340″ middle group works out to 0.162 MOA at 200 yards.
Scan-Verified 0.162 MOA Accuracy at 200 Yards
To verify the accuracy of Sierra’s measurements, we measured the middle (.338 caliber) 10-shot group with our On-Target Group Measurement software. We registered a group size reading of 0.339″ — within one-thousandth of the Sierra measurement*. The calculated group size in MOA (Minute of Angle) is 0.162. That’s amazingly good for ten rounds of big .338 caliber bullets. A FIVE-shot 0.162 MOA group at 200 would be considered excellent at any benchrest match. But remember this target has TEN shots. The current, one-target IBS world record for ten shots at 200 yards is 0.245″, set by Ed Watson in 1999.
Bevy of Barreled Actions for Bullet Testing
Sierra Bullets uses dozens of barreled actions for testing bullets in its enclosed, 200-yard test range. Each barrel has its own logbook to track the barrel’s usage.
Click Photo to Zoom
*Note, there were ten (10) shots in the group, but for simplicity we are only displaying five (5) shot circles. Adding more circles won’t change the measurement because the two most distant shots, which determine group size, ARE included.
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Bryan Richardson, owner of Powder Valley Inc. (PVI), just notified us that PVI is running a super special on big-name bullets. Get Five Hundred 6.5mm (.264) 140gr HPBT MatchKings for just $115.00. That works out to just $23 per hundred for premium match bullets. Or, for you varminters, get Five Hundred .224-Caliber BlitzKings for just $75.00. At just $15 per hundred, that’s a steal for first-run bullets.
Bryan tells us: “We just received a great buy on some custom major manufacturer bullets. We’re passing the savings on to you. Save 25-30% over what we normally sell these bullets for on our website. Check out the Specials Page and look for the bullets with a description of Custom. They won’t last long at these prices!” Questions? Feel free to call 800-227-4299 or email reload [at] powdervalleyinc.com.
Coating bullets with a friction-reducing compound such as Molybdenum Disulfide (Moly) offers potential benefits, including reduced barrel heat, and being able to shoot longer strings of fire between bore cleanings. One of the effects of reduced friction can be the lessening of internal barrel pressures. This, in turn, means that coated bullets may run slower than naked bullets (with charges held equal). To restore velocities, shooters running coated bullets are inclined to “bump up” the load — but you need to be cautious.
Be Careful When Increasing Loads for Coated Bullets
We caution shooters that when your start out with coated bullets in a “fresh barrel” you should NOT immediately raise the charge weight. It may take a couple dozen coated rounds before the anti-friction coating is distributed through the bore, and you really start to see the reduced pressures. Some guys will automatically add a grain or so to recommended “naked” bullet charge weights when they shoot coated bullets. That’s a risky undertaking.
Instead we recommend that you use “naked” bullet loads for the first dozen coated rounds through a new barrel. Use a chronograph and monitor velocities. It may take up to 30 rounds before you see a reduction in velocity of 30-50 fps that indicates that your anti-friction coating is fully effective.
We have a friend who was recently testing moly-coated 6mm bullets in a 6-6.5×47. Moly had not been used in the barrel before. Our friend had added a grain to his “naked” bullet load, thinking that would compensate for the predicted lower pressures. What he found instead was that his loads were WAY too hot initially. It took 30+ moly-coated rounds through the bore before he saw his velocities drop — a sign that the pressure had lowered due to the moly. For the rounds fired before that point his pressures were too high, and he ended up tossing some expensive Lapua brass into the trash because the primer pockets had expanded excessively.
LESSON: Start low, even with coated bullets. Don’t increase your charge weights (over naked bullet loads) until you have clear evidence of lower pressure and reduced velocity.
Procedure After Barrel Cleaning
If you shoot Moly, and clean the barrel aggressively after a match, you may want to shoot a dozen coated “foulers” before starting your record string. Robert Whitley, who has used Moly in some of his rifles, tells us he liked to have 10-15 coated rounds through the bore before commencing record fire. In a “squeaky-clean” bore, you won’t get the full “benefits” of moly immediately.
To learn more about the properties of dry lubricants for bullets, read our Guide to Coating Bullets. This covers the three most popular bullet coatings: Molybdenum Disulfide (Moly), Tungsten Disulfide (WS2 or ‘Danzac’), and Hexagonal Boron Nitride (HBN). The article discusses the pros and cons of the different bullet coatings and offers step-by-step, illustrated instructions on how to coat your bullets using a tumbler.
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At the request of our readers, we have launched a “Deals of the Week” feature. If this proves popular, we’ll try to run this every Monday. Here are some of the best deals on hardware, reloading components, and shooting accessories. Be aware that sale prices are subject to change, and once clearance inventory is sold, it’s gone for good. You snooze you lose.
1. Midsouth and Powder Valley — Hodgdon Varget and H4350
Two of the most sought-after (and hard-to-find) powders are now available, at least in one-pound versions. Midsouth Shooters Supply has Hodgdon Varget in one-pound containers for $23.30/pound, while Powder Valley has Hodgdon H4350 in one-pound containers for $23.25/pound. Act quickly — supplies are limited. NOTE: If these sources run out, Precision Reloading has both Varget AND H4350, priced at $29.49 for a one-pound container.
11/10/2015 Update: Midsouth has Sold Out of Varget. Precision Reloading still has it.
2. Grafs.com — Nikon Laser Rangefinder Scope
Now can get a quality Nikon riflescope with a built-in Laser Rangefinder for no more than you’d pay for a Rangefinder by itself. That’s right, Nikon’s advanced 2.5-10x40mm M-223 LASER IRT combines a Laser Rangefinder with a full-featured scope. This is good set-up for hunting — you don’t have to carry a separate LRF. This unit offers “one-touch” activation with range values that display for 12 seconds. That makes it easy to hold your rifle with both hands while scanning.
3. Natchez Shooters Supply — 325 Rounds .22 LR Ammo, $20.99
Now we’re talking — this is the kind of pricing on bulk rimfire ammo we used to see in the “good old days”. Act quickly, this Federal .22 LR Ammo deal won’t last long. Also, seller Natchez has a purchase limit: “Due to limited supplies and high demand this item has a 2-piece maximum order quantity per customer, per every 1 day.” So you may order two boxes per day, which will total 650 rounds. The bullets are 40 grains, solid lead.
4. CDNN Sports — Walther PK380, $339.99
Bond… James Bond. If 007 were to pack a modern-day equivalent of his Walther PPK, it would be this slim new PK380 in .380 ACP. Weighing just 19.4 ounces, the slim PK380 is easy to carry. The grip is very comfortable even for small hands, and the slide is easy to operate, making this a good choice for the ladies. The PK380 has an ambidextrous manual safety and is hammer-fired.
5. Bullets.com — New Heavy, Cast-Iron 50 BMG Front Rest
If you’re shooting a Fifty, you need lots of stability. Now there’s a big, heavy front rest designed expressly for the big .50 Caliber rifles. This new, 20″-wide cast iron rest weighs a whopping 24 pounds. Pin-to-Pin footprint is 18.9″ providing outstanding stability and resistance to rocking. The large top accepts front bags up to 8-3/4″ x 3″ (bag not included). Designed to be used either on the bench or on the ground, the new Bald Eagle Big Fifty Cast Iron Rest (Model BE1161) is available for $375.00 as an introductory special.
6. Creedmoor Sports — $50 Off Hardback Shooting Coats
As an end-of-year special, Creedmoor Sports has knocked $50.00 off its famous Hardback shooting coats. Choose from all-leather, leather + Cordura nylon, or all-Cordura. We personally like the Combo coat that uses leather in the arms/shoulders with nylon in the front. This saves weight and is a bit more comfortable in summer heat.
Yes, you can get a name-brand Ultrasonic cleaning machine for under fifty bucks. This Hornady Lock-N-Load Sonic Cleaner, which sells elsewhere for $75-$85, is available at Brownells.com this week for just $49.99. This cleaning machine holds up to 200 .223 Remington cases, or 100 .308 Winchester cases.
8. Amazon.com — Manfrotto 410 3-Axis Geared Head
Once you’ve used a geared head for your spotting scope, you’ll never want to go back to standard tripod controls. The Manfrotto 410 Junior Geared Head delivers precise 3-Axis control: 360° of pan (traverse), +90° to -30° of front tilt (elevation), and +90° to -30° of lateral tilt. When spotting, this makes it much easier to traverse from one target to another — you can move horizontally with no vertical movement. AccurateShooter’s editors use this model 410, which features a quick-release plate. This is a very good deal. This same Manfrotto 410 Geared head sells elsewhere for $270.00 or more.
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If you want to load ultra-accurate ammo and shoot very small groups, you should read this article, which we are re-publishing by popular demand. Many novice handloaders believe that neck bushing Inside Diameter (ID) size is the only important factor in neck tension. In fact, many different things will influence the grip on your bullet and its ability to release from the case neck. To learn the ins and outs of neck tension, take some time and read this article carefully.
Neck Tension (i.e. Grip on Bullets) Is a Complex Phenomenon
While we certainly have considerable control over neck tension by using tighter or looser bushings (with smaller or bigger Inside Diameters), bushing size is only one factor at work. It’s important to understand the multiple factors that can increase or decrease the resistance to bullet release. Think in terms of overall brass-on-bullet “grip” instead of just bushing size.
Bullet grip is affected by many things, such as:
1. Neck-wall thickness.
2. Amount of bearing surface (shank) in the neck.
3. Surface condition inside of neck (residual carbon can act as a lubricant; ultrasonic cleaning makes necks “grabby”).
4. Length of neck (e.g. 6mmBR neck vs. 6mm Dasher).
5. Whether or not the bullets have an anti-friction coating.
6. The springiness of the brass (which is related to degree of work-hardening; number of firings etc.)
7. The bullet jacket material.
8. The outside diameter of the bullet and whether it has a pressure ridge.
9. Time duration between bullet seating and firing (necks can stiffen with time).
10. How often the brass is annealed
— and there are others…
One needs to understand that bushing size isn’t the beginning and end of neck tension questions, because, even if bushing size is held constant, the amount of bullet “grip” can change dramatically as the condition of your brass changes. Bullet “grip” can also change if you alter your seating depth significantly, and it can even change if you ultrasonically clean your cases.
In our Shooters’ Forum a reader recently asked: “How much neck tension should I use?” This prompted a Forum discussion in which other Forum members recommended a specific number based on their experience, such as .001″, .002″, or .003″. These numbers, as commonly used, correspond to the difference between case-neck OD after sizing and the neck OD of a loaded round, with bullet in place. In other words, the numbers refer to the nominal amount of interference fit (after sizing).
While these commonly-used “tension numbers” (of .001″, .002″ etc.) can be useful as starting points, neck tension is actually a fairly complex subject. The actual amount of “grip” on the bullet is a function of many factors, of which neck-OD reduction during sizing is just one. Understanding these many factors will help you maintain consistent neck tension as your brass “evolves” over the course of multiple reloadings.
Seating Depth Changes Can Increase or Decrease Grip on Bullet
You can do this simple experiment. Seat a boat-tail bullet in your sized neck with .150″ of bearing surface (shank) in the neck. Now remove the bullet with an impact hammer. Next, take another identical bullet and seat it with .300″ of bearing surface in another sized case (same bushing size/same nominal tension). You’ll find the deeper-seated bullet is gripped much harder.
Neck-Wall Thickness is Important Too
I have also found that thinner necks, particularly the very thin necks used by many PPC shooters, require more sizing to give equivalent “grip”. Again, do your own experiment. Seat a bullet in a case turned to .008″ neckwall thickness and sized down .003″. Now compare that to a case with .014″ neckwall thickness and sized down .0015″. You may find that the bullet in the thin necks actually pulls out easier, though it supposedly has more “neck tension”, if one were to consider bushing size alone.
In practical terms, because thick necks are less elastic than very thin necks, when you turn necks you may need to run tighter bushings to maintain the same amount of actual grip on the bullets (as compared to no-turn brass). Consequently, I suspect the guys using .0015″ “tension” on no-turn brass may be a lot closer to the guys using .003″ “tension” on turned necks than either group may realize.
Toward a Better Definition of Neck Tension
As a convenient short-cut, we tend to describe neck tension by bushing size alone. When a guy says, “I run .002 neck tension”, that normally means he is using a die/bushing that sizes the necks .002″ smaller than a loaded round. Well we know something about his post-sizing neck OD, but do we really have a reliable idea about how much force is required to release his bullets? Maybe not… This use of the term “neck tension” when we are really only describing the amount of neck diameter reduction with a die/bushing is really kind of incomplete.
My point here is that it is overly simplistic to ask, “should I load with .001 tension or .003?” In reality, an .001″ reduction (after springback) on a thick neck might provide MORE “grip” on a deep-seated bullet than an .003″ reduction on a very thin-walled neck holding a bullet with minimal bearing surface in the neck. Bushing ID is something we can easily measure and verify. We use bushing size as a descriptor of neck tension because it is convenient and because the other important factors are hard to quantify. But those factors shouldn’t be ignored if you want to maintain consistent neck tension for optimal accuracy.
Consistency and accuracy — that’s really what this all about isn’t it? We want to find the best neck tension for accuracy, and then maintain that amount of grip-on-bullet over time. To do that you need to look not only at your bushing size, but also at how your brass has changed (work-hardened) with time, and whether other variables (such as the amount of carbon in the neck) have changed. Ultimately, optimal neck tension must be ascertained experimentally. You have to go out and test empirically to see what works, in YOUR rifle, with YOUR bullets and YOUR brass. And you may have to change the nominal tension setting (i.e. bushing size) as your brass work-hardens or IF YOU CHANGE SEATING DEPTHS.
Remember that bushing size alone does not tell us all we need to know about the neck’s true “holding power” on a bullet, or the energy required for bullet release. True bullet grip is a more complicated phenomenon, one that is affected by numerous factors, some of which are very hard to quantify.
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High-BC 7mm bullets are favored by many of the top long-range and F-Class (Open) shooters. Now, thanks to Sierra Bullets, there is a new “heavy-weight contender” in the 7mm match bullet category. Sierra has just introduced an all-new 183 grain 7mm HPBT MatchKing, part # 1983. This impressive new projectile boasts a 0.707 G1 Ballistic Coefficient (at 2300+ fps), plus — get this — it comes “tipped” from the factory. The final meplat tipping operation ensures a higher, more uniform BC. Recommended barrel twist rate is 1:8″ or faster.
Sierra says its new 183gr 7mm MatchKing has a modern, low-drag shape: “A sleek 27-caliber elongated ogive and a final meplat reducing operation (pointing) provide an increased ballistic coefficient for optimal wind resistance and velocity retention. To ensure precise bullet to bore alignment, a unique bearing surface to ogive junction uses the same 1.5 degree angle commonly found in match rifle chamber throats.
The new 7mm 183gr HPBT bullets will be available in boxes of 500 bullets (#1983C) with MSRP of $256.34 per box and boxes of 100 bullet (#1983) with MSRP of $51.80 per box. NOTE: Sierra states that “MatchKing® and Tipped MatchKing® bullets are not recommended for most hunting applications.”
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In this video, Bryan Litz of Applied Ballistics talks about Density Altitude and the effect of atmospheric conditions on bullet flight. Bryan explains why you must accurately account for Density Altitude when figuring long-range trajectories.
Bryan tells us: “One of the important elements in calculating a fire solution for long-range shooting is understanding the effect of atmospherics. Temperature, pressure, and humidity all affect the air density that the bullet’s flying through. You can combine all those effects into one number (value) called ‘Density Altitude’. That means that you just have one number to track instead of three. But, ultimately, what you are doing is that you are describing to your ballistics solver the characteristics of the atmosphere that your bullet’s flying through so that the software can make the necessary adjustments and account for it in its calculations for drop and wind drift.”
Density altitude is the altitude relative to the standard atmosphere conditions (ISA) at which the air density would be equal to the indicated air density at the place of observation. Density altitude can be calculated from atmospheric pressure and temperature (assuming dry air). Here is the formula:
Air is more dense at lower elevations primarily because of gravity: “As gravity pulls the air towards the ground, [lower] molecules are subject to the additional weight of all the molecules above. This additional weight means the air pressure is highest at sea level, and diminishes with increases in elevation”.*
Both an increase in temperature, decrease in atmospheric pressure, and, to a much lesser degree, increase in humidity will cause an increase in density altitude. In hot and humid conditions, the density altitude at a particular location may be significantly higher than the true altitude.
In 2016, Hornady will introduce new hunting and match bullets with high-tech, heat resistant tips. Hornady developed the new “Heat Shield” bullet tips after Doppler Radar testing showed that the Ballistic Coefficients (BCs) of old-style tipped bullets were degrading in flight in an unexplained manner. Hornady’s engineers theorized that the old-style plastic bullet tips were deforming in flight due to heat and pressure. Hornady claims this problem occurred with high-BC (0.5+ G1) tipped bullets from a variety of manufacturers. Hornady’s testers believed that, after 150 yards or so, the tips on high-BC bullets were actually melting at the front. That enlarged the meplat, resulting in increased drag.*
Consequently, Hornady developed a new type of bullet tip made from a heat-resistant polymer. Further long-range Doppler Radar testing seemingly confirmed that bullets equipped with the new tips did not suffer from the BC loss previously found. This allowed the bullets to maintain a higher, more consistent BC during the entire trajectory. The end result is a bullet with reduced vertical dispersion at long range (or so Hornady claims).
New Hornady ELD-X Hunting Bullets
For 2016, Hornady will bring out two lines of projectiles using the new tips. The first line of bullets, designed for hunting, will be called ELD-X, standing for “Extreme Low Drag eXpanding”. These feature dark red, translucent, heat-resistant tips. With interlock-style internal construction, these hunting projectiles are designed to yield deep penetration and excellent weight retention. Hornady will offer seven different ELD-X bullet types, ranging in weight from 143 grains (6.5mm) to 220 grains (.30 Cal):
NOTE: We don’t know if the stated BC values are based on drag models or actual range testing. These new ELD-X hunting bullets will be loaded into a new line of Precision Hunter Ammo for a variety of popular hunting cartridges.
New Hornady ELD Match Bullets
Along with its new hunting bullets, Hornady is coming out with a line of ELD Match bullets as well. Hornady’s engineers say the new molded “Heat Shield Tip” should be a boon to competitive shooters: “You can’t point up that copper [tip] as consistently as you can mold a plastic tip. With the ELD Match line, and the Heat Shield Tip technology… we now have a perfected meplat. These bullets allow you to shoot groups with less vertical deviation, or less vertical stringing, because the bullets are exact in their drag [factor].” There are currently four bullets in the ELD Match line:
Hornady will offer factory ammunition loaded with ELD Match bullets, starting with 6.5 Creedmoor ammo loaded with the 140gr ELD, and .338 Lapua Magnum ammo loaded with the 285gr ELD.
Better Tips Make a Difference — But other Factors Are Important
Hornady claims that its new Heat Shield Tips are more uniform than the meplats on conventional jacketed, hollow-point bullets. This, Hornady says, should provide greater bullet-to-bullet BC consistency than is possible with conventional, non-tipped bullets.
We have heard such claims before. Plastic tips are good, so long as they are inserted perfectly in the bullet. But sometimes they are crooked (off-axis) — we’ve seen that with various brands of tipped projectiles. Other factors will affect bullet performance as well, such as bullet weight, bullet diameter, and bullet bearing surface length. Even with perfectly uniform bullet tips, if bullet weights or diameters are inconsistent across a sample, you can still have accuracy issues (and pressure-related velocity variances). Likewise, if the bearing surface lengths vary considerably from one bullet to the next, this can increase velocity spread and otherwise have a deleterious effect on accuracy.
So, overall, we think Hornady has probably engineered a better bullet tip, which is a good thing. On the other hand there are many other factors (beyond tip uniformity) involved in long-range bullet performance. It will be interesting to test the new ELD Match bullets to see how they compare with the best hollow point jacketed bullets from other manufacturers.
MORE TECHNICAL DETAILS
* Hornady’s Chief Ballistician Dave Emary authored a technical report based on the Doppler Radar testing of a variety of tipped Bullets. CLICK HERE for Emary Report. Here are some of the report’s key observations and conclusions:
After early testing of prototype bullets it was observed that all currently manufactured tipped projectiles’ drag curves were convex, not concave and that abnormally low ballistic coefficients were being observed over long ranges. The drag was rapidly increasing at high velocities.
At this point extensive testing was done with all types of commercially-available tipped projectiles. They all exhibited this behavior to a greater or lesser extent depending on their ballistic coefficient and launch velocity. Most projectiles exhibited BCs relatively close to published values for 150 to 200 yards of flight. Beyond these distances they all showed BCs substantially below published values.
It was obvious that something was changing in the tipped projectiles to cause a rapid increase in drag at higher velocities. The drag increases were most noticeable from 100 to about 500 yards. Drag increases stopped at velocities below approximately 2,100 fps. This behavior was not observed with hollow point or exposed lead (spitzer) style designs. The problem magnified as the velocity was increased. The problem was worse for heavier, higher-BC projectiles that maintained higher velocities longer. After some consideration the answer was obvious and one that several people had wondered about for some time but had no way to prove their thoughts.
The tip of a bullet at 3,000 fps will see temperatures as high as 850 degrees F and decreasing as
the bullet slows down. These temperatures on the tip were a known fact. What wasn’t known was how long it would take at these peak and decreasing temperatures for the polymer tips to begin showing effects, if at all. As it turns out it is within the first 100 yards of flight. Currently-used polymers in projectile tips begin to have properties like rubber at approximately -65 to 50 degrees F and will melt at 300 to 350 degrees F, depending on the exact polymer.
All current polymer-tipped projectiles have tips that are at best softening and deforming in flight and under many circumstances melting and badly deforming. To cut through a lot of technical discussion the problem becomes worse at higher ambient air temperatures (summer) and higher launch velocities. Projectiles that have a high BC and retain velocity well see higher stagnation temperatures for longer lengths of time and have greater degradation of the tip. Simply put it is a heat capacity problem –temperature times time. This makes BCs for current tipped projectiles a rough average over some distance, dependent on atmospheric conditions and muzzle velocity, and does not allow the accurate prediction of downrange ballistics much beyond 400 yards.
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At the recent IBS 600-Yard Nationals, the 6mm Dasher cartridge was the most popular chambering for both Light Guns and Heavy Guns. The Dasher, a 40° improved version of the 6mmBR Norma case, can definitely shoot — no question about that. But the Dasher has one less-than-ideal feature — its very short neck. This makes it more problematic to shoot a wide variety of bullet types — short bullets as well as long. In addition, the short neck makes it harder to “chase the lands” over time.
For those folks who like the performance of the 6mm Dasher, but prefer a longer neck, there is an excellent alternative — the 6mm BRDX. This wildcat shares the 40° shoulder of the Dasher and has nearly the same capacity. Like the Dasher, the 6 BRDX can drive 100-107gr bullets to the same 3000-3050 FPS accuracy node. But the 6 BRDX has a longer neck than the Dasher. Depending on your “blow length”, the 6 BRDX will typically give you about .030″ to .035″ more usable neck length. That may not sound like much, but it is very useful if you have a longish (.110″+) freebore and you still want to shoot shorter bullets in the lands for some applications.
Your editor has a 6mm BRDX and I really like it. The neck is long enough to let me shoot 90-grainers loaded into the lands as well as 105-grainers. Fire-forming is pretty easy. I just load very long (so there is a firm jam) and shoot with 30.0 grains of Varget and a 100+ grain bullet. With a Brux barrel, my BRDX easily shoots quarter-MOA, with some 100-yard groups in the ones in calm conditions. This is with a Stiller Viper Action, and Shehane ST-1000 stock bedded by Tom Meredith.
6mm BRDX Reamer, Dies, and Hydro-Forming Service
It’s not difficult to set up a rifle to run the 6 BRDX. Dave Kiff’s Pacific Tool & Gauge has the reamer (just tell him the freebore you want). Whidden Gunworks offers excellent BRDX sizing and seating dies. And if you don’t like fire-forming, give Darrell Jones of DJsbrass.com a call. Darrell can hydro-form 6 BRDX brass and even turn the necks to your specs. Darrell’s hydro-forming service saves you time and preserves precious barrel life.
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Efficient cartridges make excellent use of their available powder and case/bore capacity. They yield good ballistic performance with relatively little recoil and throat erosion.
Cartridge Efficiency: A Primer (pun intended!)by USAMU Staff
Each week, the U.S. Army Marksmanship Unit (USAMU) publishes a reloading article on its Facebook Page. In this week’s article, the USAMU discusses cartridge case efficiency and its benefits. While this is oriented primarily toward NRA High Power Rifle and Long Range (1000-yard) competition, these factors also apply to medium/big game hunters. Assuming one’s rifle and ammunition are accurate, key considerations include ballistic performance (i.e., resistance to wind effects, plus trajectory), recoil, and throat erosion/barrel life.
Efficient cartridges make excellent use of their available powder and case/bore capacity. They yield good ballistic performance with relatively little recoil and throat erosion. A classic example in the author’s experience involved a featherweight 7x57mm hunting/silhouette rifle. When loaded to modern-rifle pressures, just 43-44 grains of powder pushed a 139gr bullet at 2900 fps from its 22” barrel. Recoil in this light rifle was mild; it was very easy to shoot well, and its performance was superb.
An acquaintance chose a “do everything” 7mm Remington Magnum for use on medium game at short ranges. A larger, heavier rifle, it used ~65 grains of powder to achieve ~3200 fps with similar bullets — from its 26″ barrel. Recoil was higher, and he was sensitive to it, which hampered his shooting ability.
Similarly efficient calibers include the 6mm BR [Norma], and others. Today’s highly-efficient calibers, such as 6mm BR and a host of newer developments might use 28-30 grains of powder to launch a 105-107gr match bullet at speeds approaching the .243 Winchester. The .243 Win needs 40-45 grain charges at the same velocity.
Champion-level Long Range shooters need every ballistic edge feasible. They compete at a level where 1″ more or less drift in a wind change could make the difference between winning and losing. Shooters recognized this early on — the then-new .300 H&H Magnum quickly supplanted the .30-06 at the Wimbledon winner’s circle in the early days.
The .300 Winchester Magnum became popular, but its 190-220gr bullets had their work cut out for them once the 6.5-284 and its streamlined 140-142gr bullets arrived on the scene. The 6.5-284 gives superb accuracy and wind performance with about half the recoil of the big .30 magnums – albeit it is a known barrel-burner.
Currently, the 7mm Remington Short Action Ultra-Magnum (aka 7mm RSAUM), is giving stellar accuracy with cutting-edge, ~180 grain bullets, powder charges in the mid-50 grain range and velocities about 2800+ fps in long barrels. Beyond pure efficiency, the RSAUM’s modern, “short and fat” design helps ensure fine accuracy relative to older, longer cartridge designs of similar performance.
Recent design advances are yielding bullets with here-to-fore unheard-of ballistic efficiency; depending on the cartridge, they can make or break ones decision. Ballistic coefficients (“BC” — a numerical expression of a bullet’s ballistic efficiency) are soaring to new heights, and there are many exciting new avenues to explore.
The ideal choice [involves a careful] balancing act between bullet BCs, case capacity, velocity, barrel life, and recoil. But, as with new-car decisions, choosing can be half the fun!
Factors to Consider When Evaluating Cartridges
For competitive shooters… pristine accuracy and ballistic performance in the wind are critical. Flat trajectory benefits the hunter who may shoot at long, unknown distances (nowadays, range-finders help). However, this is of much less importance to competitors firing at known distances.
Recoil is an issue, particularly when one fires long strings during competition, and/or multiple strings in a day. Its effects are cumulative; cartridges with medium/heavy recoil can lead to shooter fatigue, disturbance of the shooting position and lower scores.
For hunters, who may only fire a few shots a year, recoil that does not induce flinching during sight-in, practice and hunting is a deciding factor. Depending on their game and ranges, etc., they may accept more recoil than the high-volume High Power or Long Range competitor.
Likewise, throat erosion/barrel life is important to competitive shooters, who fire thousands of rounds in practice and matches, vs. the medium/big game hunter. A cartridge that performs well ballistically with great accuracy, has long barrel life and low recoil is the competitive shooter’s ideal. For the hunter, other factors may weigh more heavily.
Cartridge Efficiency and Energy — Another Perspective
Lapua staffer Kevin Thomas explains that efficiency can be evaluated in terms of energy:
“Cartridge efficiency is pretty straight forward — energy in vs. energy out. Most modern single-based propellants run around 178-215 ft/lbs of energy per grain. These figures give the energy potential that you’re loading into the rifle. The resulting kinetic energy transferred to the bullet will give you the efficiency of the round. Most cases operate at around 20-25% efficiency. This is just another way to evaluate the potential of a given cartridge. There’s a big difference between this and simply looking at max velocities produced by various cartridges.”
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Berger has released two important informational updates for its line-up of bullets. First, the Ballistics Coefficients (BCs) have been updated for the vast majority of bullets Berger sells. In addition, G7 model BCs are being provided for most of the bullets. You will want to use the updated BC data, which is based on actual testing of recent production lots of bullets.
Second, Berger is now providing a dual twist-rate recommendation for most bullets. Berger is now lists a “minimum” barrel twist rate as well as an “optimal” twist rate. To get maximum long-range performance from your bullets, use a barrel with the “optimal” rate of twist.
CLICK HERE for the latest Berger Quick Reference Sheets with updated BCs and new Optimal Twist Rates. Eric Stecker, Berger President says: “We have tested every lot of bullets produced in the last several years to bring you these updated numbers for all of our bullets.”
Ballistic Coeffificent (BC) Updates with G7 Data
Berger notes: “We have updated all of our Ballistic Coefficients to be even more accurate.
Prior to 2008, all of Berger Bullets’ BCs were calculated using a computer prediction. Early in 2009, we began measuring BCs with live-fire testing. As a result, Berger’s BCs were updated and G7 BCs were also made available. This represented a dramatic improvement in the accuracy of performance data at that time. Since 2009, the BCs assessed for Berger Bullets have not been updated. As part of our ongoing effort to provide shooters with the best information possible, Berger has been testing every lot of bullets produced for the last several years. The result is updated and highly accurate running averages of BCs for recent production lots.
Here are some of the Updated BC Values for popular Berger Target (Match) Bullets:
G7 Form Factor Addition
Berger also added the G7 form factor to the Ballistics Quick Reference Sheet. The analysis of form factors can be very useful when considering a bullet’s long range performance potential. Going by BC alone can be deceptive since BC includes the weight and caliber of the bullet. Form factor indicates how much drag the bullet has, which is a very important consideration for all bullets of all calibers.
NEW Dual Twist-Rate Recommendations
Recommended twist rates for bullets are commonly listed as a single value, such as 1:12” (one rotation in 12″ of barrel travel). This may be overly simplistic. There is a big gray area of marginal stability in which bullets can fly with good accuracy, but with a reduced (i.e. sub-optimal) Ballistic Coefficient. Recognizing this reality, Berger is now listing two twist rates for each bullet it makes. The first is the minimum twist needed for good accuracy, which Berger has always recommended. The second is the new optimal twist rate, which is the twist that will stabilize the bullet to a level which achieves its full performance (BC) potential. CLICK HERE For more information.
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Redding Reloading is now providing Advanced Handloader’s Data Sheets in printable PDF format. This FREE form allows hand-loaders to document their tool settings, bushing size, powder charge, load specs (COAL etc.), and case prep status. In addition, the form allows you to enter your load testing information, complete with chronograph data, group size, zero range, and wind/temp conditions. With this single, handy form you can document all the vital information for a particular cartridge and load.
We’ve seen various reloading log templates, but this Redding form (shown below) is better than most because it combines both reloading data AND range-test data in one place. You can see all key details of the reloading process (tool settings etc.) plus the end results — how the load actually performed over the chronograph and on paper. This form allows the user to capture a large amount of information for later use, while accurately track load development. Go to Download Page.
FREE Ammunition Box Label Template
Redding Reloading has also developed a printable template for your ammo boxes (see photo at top of article). This lets you put all vital load info on your ammo boxes. There are fields for: Date, Cartridge, Powder, Grains, Bullet, Weight, Primer, Case type. Designed for Avery 5260 (or similar) label sheets, this template allows you to print 30 labels at one time. You can purchase the Avery 5260 peel-off printable label sheets at any office supply store.
Applied Ballistics LLC will release updated editions of two popular resource books: Applied Ballistics for Long-Range Shooting (3rd Edition) and Ballistic Performance of Rifle Bullets (2nd Edition). Retail price is $54.95 for each title, or $94.95 if purchased together. Pre-orders are now being accepted with a $5 discount per book. You can pre-order the new editions through the Applied Ballistics store. The new editions are expected to ship by the second week of December.
Applied Ballistics for Long Range Shooting (ABLRS), Bryan Litz’s “Magnum Opus”, will have significant enhancements. New for the Third Edition is content on Weapon Employment Zone (WEZ) analysis. WEZ analysis is the study of hit percentage, and how that will be affected by the uncertainties in your environment. Existing academic material is augmented with modern experimental findings. The Third Edition also includes a CD-ROM disc with Applied Ballistics’ latest version of its ballistic software. NOTE: The third edition of ABLRS does NOT include the library of bullet data. That bullet library now exists as a separate reference book: Ballistic Performance of Rifle Bullets.
Ballistic Performance of Rifle Bullets — Data for 533 Bullets AND Rimfire Ammo
The updated, Second Edition of Ballistic Performance of Rifle Bullets contains the current library of all modern bullets tested by the Applied Ballistics Laboratory. Expanding on the First Edition, which had data on 400 bullets from .22 to .408 caliber, this Second Edition contains data on 533 bullets from .22 through .50 caliber. In addition to the centerfire bullet data, the Second Edition contains live fire data on 90 types of rimfire ammo which were all tested for muzzle velocity and BC through five different barrels of various twist/length configurations. This library of experimental test data is the most extensive and accurate resource ever assembled for small arms bullets. Numerous modern ballistics programs draw from the library of tested BCs that are published in this book.
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Need a simple, easy-to-use drop chart for your rifle? Something you can tape right to the buttstock? Then check out Hornady’s handy Online Ballistics Calculator. This user-friendly calculator will compute your drops accurately, and output a handy “Cheat Sheet” you can print and attach to your rifle. Simply input G1 or G7 BC values, muzzle velocity, bullet weight, zero range and a few other variables. Click “Calculate” and you’re good to go. You can select the basic version, or an advanced version with more data fields for environmental variables (altitude, temperature, air pressure, and humidity). You can also get wind drift numbers by inputing wind speed and angle.
Conveniently, on the trajectory output, come-ups are listed in both MOA and Mils — so this will work with either MOA clicks or Mil-based clicks. There are more sophisticated ballistics solvers available on the web (such as the outstanding Applied Ballistics Online Calculator), but the Hornady Calculator is very simple and easy to use. If you just want a basic drop chart, you may want to check this out.
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Norma has released a fascinating video showing how bullet, brass, and ammunition are produced at the Norma Precision AB factory which first opened in 1902. You can see how cartridges are made starting with brass disks, then formed into shape through a series of processes, including “hitting [the cup] with a 30-ton hammer”. After annealing (shown at 0:08″), samples from every batch of brass are analyzed (at multiple points along the case length) to check metal grain structure and hardness. Before packing, each case is visually inspected by a human being (3:27″ time-mark).
The video also shows how bullets are made from jackets and lead cores. Finally, you can watch the loading machines that fill cases with powder, seat the bullets, and then transport the loaded rounds to the packing system. In his enthusiasm, the reporter/narrator does sometimes confuse the term “bullets” and “rounds” (5:00″), but you can figure out what he means. We definitely recommend watching this video. It’s fascinating to see 110-year-old sorting devices on the assembly line right next to state-of-the art, digitally-controlled production machinery.
Video tip by EdLongrange. We welcome reader submissions.
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This article first appeared in 2014. We are reprising it at the request of many readers who are fans of the .30-06 cartridge.
The “Old Warhorse” .30-06 Springfield cartridge is not dead. That’s the conclusion of Forum member Rick M., who has compared the 1000-yard performance of his .30-06 rifle with that of a rig chambered for the more modern, mid-sized 6.4×47 Lapua cartridge. In 12-16 mph full-value winds, the “inefficient and antiquated” .30-06 ruled. Rick reports:
“I was shooting my .30-06 this past Sunday afternoon from 1000 yards. The wind was hitting 12-16 mph with a steady 9 O’clock (full value) wind direction. My shooting buddy Jeff was shooting his 6.5×47 Lapua with 123gr Scenar bullets pushed by Varget. Jeff needed 13 MOA left windage to keep his 6.5x47L rounds inside the Palma 10 Ring. By contrast I only needed 11.5 MOA left windage with my .30-06. I was shooting my ’06 using the 185gr Berger VLD target bullet with H4350. I managed the same POI yet the .30-caliber bullet only needed 11.5 MOA windage. That’s significant. From this experience I’ve concluded that the Old Warhorse ain’t quite dead yet!”
Rick likes his “outdated” .30-06 rifle. He says it can deliver surprisingly good performance at long range:
“To many of the younger generation, the Old Warhorse .30-06 is ‘outdated’ but I can guarantee that the .30-06 Springfield is a VERY ACCURATE cartridge for 1000-yard shooting (and even out further if need be). With some of the advanced powders that we have today, the .30-06 will surprise many shooters with what it’s capable of doing in a good rifle with the right rate of twist. My rifle has a 1:10″ twist rate and I had it short-throated so that, as the throat erodes with time, I could just seat the bullets out further and keep right on shooting. My recent load is Berger 185gr Target VLDs pushed by IMR 4350. This is a very accurate load that moves this bullet along at 2825 fps.”
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BIG news in the shooting sports industry — Ruger has entered the ammo business. Ruger now offers high-tech handgun ammunition, using licensed polymer-composite, lead-free bullet technology. According to the Shooting Wire: “Ruger’s new lead-free ammunition will be produced under a licensing agreement with Savannah, Georgia-based PolyCase Ammunition.”
Ruger’s new ARX line of lead-free ammo features injection-molded bullets that are much lighter than conventional projectiles, caliber by caliber: 56 grains for .380 ACP, 74 grains for 9x19mm, 107 grains for .40 SW, and 114 grains for .45 ACP. The lighter bullets fly faster, but ARX ammo still offers reduced perceived recoil.
Ruger ARX Ammo with Injection-Molded Matrix Bullets
The fluted projectiles are injection-molded from a copper/polymer matrix. This offers many advantages. First, being completing lead-free, these bullets can be used at indoor facilities that prohibit lead-based ammo. Second, because the composite bullets weigh 30% less than comparable lead-based projectiles, shooters experience noticeably less recoil (even though velocities are higher). Third, the composite matrix bullet has low-ricochet properties. When these bullets strike metal, they are designed to disintegrate (into a powder), rather than ricochet. This makes them well-suited for indoor use, or use with metal plates.
Shooting Wire Editor Jim Shepherd reports that ARX ammo delivers on its low-recoil promise: “Having spent time testing the PolyCase ammunition (largely in Ruger firearms), I know the reduction in felt recoil isn’t just hype. While firing PolyCase ARX ammunition in calibers ranging from .380 in small concealed carry pistols (including a Ruger’s LCP) up to .458 SOCOM in modern sporting rifles, the lessened felt recoil was noticeable.”
PolyCase Molded Bullet Design Technology
For over a century most bullets have been mass-produced with a process called cold-forming. Lead and copper were shaped with brute force in punches and dies to create projectiles. While this is still a viable and effective way to produce bullets, other manufacturing methods are now available. By applying injection-molding technology, Polycase has developed a new type of bullet that has many advantages, as least for handgun applications. Bullets weigh approximately 70% as much as lead bullets with similar profiles. Lighter weight means higher velocities and less recoil. In addition, PolyCase bullets are lead-free, and low-ricochet — two qualities important for indoor and close-range training. The injection-molding process also reduces weight variations (compared to cast lead bullets), and ensures excellent concentricity. Molding also allows unique shapes that are impossible to produce with conventional bullet-making methods (see photo).
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These four photos show the substantial changes in the shock wave and turbulence patterns for the same 7.5mm bullet at different velocities. The “M” stands for Mach and the numerical value represents the velocity of the bullet relative to the speed of sound at the time of the shot. Photos by Beat Kneubuehl.
“Going transonic” is generally not a good thing for bullets. The bullet can lose stability as it enters the transonic zone. It can also become less slippery, losing BC as a consequence of dynamic instability. In this video, Bryan Litz of Applied Ballistics analyzes what happens to bullet stability (and BC) as projectiles approach the speed of sound. Transonic effects come into play starting about Mach 1.2, as the bullet drops below 1340 fps.
Transonic Ballistics Effects Explainedby Bryan Litz
What happens when the bullet slows to transonic speed, i.e. when the bullet slows to about 1340 feet per second? It is getting close to the speed of sound, close to the sound barrier. That is a bad place to fly for anything. In particular, for bullets that are spin-stabilized, what the sound barrier does to a bullet (as it flies near Mach 1) is that it has a de-stabilizing effect. The center of pressure moves forward, and the over-turning moment on the bullet gets greater. You must then ask: “Is your bullet going to have enough gyroscopic stability to overcome the increasing dynamic instability that’s experienced at transonic speed?”
Some bullets do this better than others. Typically bullets that are shorter and have shallow boat-tail angles will track better through the transonic range. On the contrary, bullets that are longer… can experience a greater range of pitching and yawing in the transonic range that will depress their ballistic coefficients at that speed to greater or lesser extents depending on the exact conditions of the day. That makes it very hard to predict your trajectory for bullets like that through that speed range.
When you look at transonic effects on stability, you’re looking at reasons to maybe have a super-fast twist rate to stabilize your bullets, because you’re actually getting better performance — you’re getting less drag and more BC from your bullets if they are spinning with a more rigid axis through the transonic flight range because they’ll be experiencing less pitching and yawing in their flight.
To determine how bullets perform in the “transonic zone”, Bryan did a lot of testing with multiple barrels and various twist rates, comparing how bullets act at supersonic AND transonic velocities. Bryan looked at the effect of twist rates on the bullets’ Ballistic Coefficient (BC). His tests revealed how BC degrades in the transonic zone due to pitching and yawing. Bryan also studied how precision (group size) and muzzle velocity were affected by twist rates. You may be surprised by the results (which showed that precision did not suffer much with faster barrel twist rates). The results of this extensive research are found in Bryan’s book Modern Advancements in Long Range Shooting.
Bryan notes: “A lot of gunpowder was burned to get these results and it’s all published in layman’s terms that are easy to understand”. If you’re interested in learning more about transonic bullet stability, you may want to pick up a copy of Bryan’s book.
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